thin clay wall option: wattle & daub
weave the wall shape, coat with wet clay & straw mix
Benefits:
thin walls
faster construction
Challenge:
you likely need to #DIY because there are very few trained inatllers
they're still heavy, so you need to ensure your structure can support

solid clay walls options:
sculpted #cob
stacked #adobe bricks
tamped #rammedearth
Each option = #thermalmass wall made from local materials
Benefits:
sound control
reduce internal temperature swings
works w/ #passivesolar design
block EMFs
Cons:
time-consuming
thickness takes up space inside
heavy